Method and apparatus for removing fire rings from rotary kilns



Nov. 10, 1942. w c E 2,301,855 METHOD AND APPARATUS FOR REMOVINGFIRERINGS FROM ROTARY KILNS Filed June 4, 1941 2 Sheets-Sheet l Nov. 10,1942'.

Filed June 4, 1941 W R. CLIFFE METHOD AND APPARATUS FbR REMQVING FIRERINGS FROM ROTARY KILNS 2 Sheets-Sheet 2 11M)? mm;

and down a given UNHTED STAT METHOD AND APPARATUS FOR REMOVING FIRERINGS FROM ROTARY KILNS WalterB... Clifie, Hershey, Pa., assignor ofonehalf to Cardox Corporation, Chicago, 111., a corporation of IllinoisApplication June 4, 1941, Serial No. 396,632

12 Claims. (or. 263-32) This invention relates to new and usefulimprovements in methods and apparatus for removing fire rings fromrotary kilns employed in the production of such materials as. lime,magnesite, refractory dolomite, or the like; and in.

any processes employing rotary kilns in connection with which theremoval of fire rings:is a

problem.

Although certain differences will be found in the character, location,etc, of the fire rings; which are formed in rotary kilns employed indifferent processes, these differences are immaterial insofar ascarrying out the steps of the present method and making use of thepresent apparatus is concerned. For that reason itis believed tobejsuficient to only describe the present invention in connection withits application to the removal of fire rings from rotary lime kilns andit will be understood that the description is intended to embrace theremoval of fire rings from rotary kilns employed in all other analogousprocesses.

As a typical example, let us consider a rotary cylinder lime kiln whichis 290 feet long. and 7 feet 5 inches in diameter. such an inclinedcylinder will be of an inch in thickness and will have applied to theinterior thereof a 7 inch lining which is usually formed of bricks madefrom suitable refractory material. This lining will leave a bore orinner chamber which is 6 feet 9 inches in diameter.

During normal operation of such akiln, pulvercarbonate are delivered tothe cylinder as it is rotated. The burningof the fuel accomplishesdisassociation of the calcium carbonate and the resultant lime isspilled at the discharge point of the kiln.

The fire ring, which is formed by the accumulation of slag on the bricklining, makes its ap- The steel shell of Y the method to be employedforrendering the kiln suitable for further use. It is the presentpractice ized coal, or some other suitable fuel, and calcium pearanceany time after the burning infof the kiln. The ring may cover from 2 toapproximately 10 feet of the length of the kiln. Its location may varyconsiderably in different kilns and accumulation of the slag fire ringand lowering of. the efficiency of the kiln can be permitted to continueuntil the ring nearly bridges or closes the bore through the cylinder atwhich time it be.-

comes necessary to reach a decision regarding 55 tudinally of the kilnand its great mass renders to either shut down the kiln temporarilywhile an attempt is made ,to enlarge the opening in the formation to asufficient extent to permit the operation to be resumed or the kiln mustbe completely burned out and removed from the production line. In eithercase, the feeding of fuel and material is stopped.

If the operator of the kiln is confronted with a pressing need forproduction, he will probably decideto shut down the kiln temporarilywhile an attempt is made to enlarge the opening in the fire ringformation. If the fire ring has formed relatively close to thedischargeend of the kiln, the operator may employ either alarge watercooled boring tool or a huge water cooled poker; If thejboring tool isselected, it is adjusted with respect to the formation and the kiln isrotated while the tool makes the desired cut. The slagformation may becut away to a desired depth in this manner. The total loss of operatingtime for this type of removal usually amounts to about six hours.However, the product iscontaminated with fine cuttings from theformation and a high quality product may not be obtainable for manyadditional hours.

If. the hugewater poker is the selected implement, the kiln is stoppedand the poker is manipulated by the ten or twelve men requiredto handlethe same. The function of the poker is to chip or break away the innerportion of the ring. This. method of removal of the inner portion of theformation, to enlarge the hole through said formation, also requiresabout five or six hours but it is the least desirable of the severalmethods employed at the present time. .This is due to the fact that thetreatment is very injurious to the refractory lining and the water fromthe poker has a ruinous effect on numerous products.

Probably the preferred method for partial fire ring removal involves theuse of a kiln gun which fires slugs, weighing as much as five ounces,into the formation. It is the function of this gun to direct the slugssothat the top or high points of the formation are trimmed down and theopening is, thereby, enlarged. This method of partial removal has verydefinitaunavoidable limitations which may be noted as follows:

It usually requires in the neighborhoodof 1000 shells to remove asufficient amount of the slag formation to render the kiln suitable forfurther use. As the slag formation ages, it grows longithe kiln gunentirely ineffective. When this point is reached, a complete shut downis necessary. The shattering effect of the slugs on the slag formationhas a tendency to pulverize the material which in some cases causes thekiln charge to be contaminated, thereby considerably reducing its value.

If either of the above noted methods of partial slag removal isemployed. for keeping a kiln in operation, regular trimmings have beenfound to be the best practice. This will be obvious when it isconsidered that if the fire ring is allowed to build up to too great athickness, the charge impounded behind the ring will fiush forward inuncontrolled quantities when the ring is trimmed down. Th productobtained in this manner is of questionable quality and it often must bewasted.

If the operator decides to burn out and take the kiln off the productionline, the feed of fuel and material is usually stopped and rotation ofthe kiln is continued for a period of four or five hours to permit thecharge to be rotated therefrom." Of course, that portion of the chargewhich remains impounded behind the fire ring will not be dischargedduring this period. Only approximately 20% of the charge obtained duringthis period can be considered as a usable product.

It ordinarily requires a minimum of twentyfour hours before men canenter the kiln to attempt to remove the slag after all obtainablematerial has been drawn off. It requires very rapid chilling of the kilnto permit men to enter the same in this minimum period of twenty-fourhours and this rapid chilling invariably adversely affects the lining.It usually is discovered that only the surface of the slag is reallycool enough to be worked after such a short chilling period. When thisapparently cool surface is removed, a red hot interior usually isencountered. The 'work of removing slag under these conditions isextremely difficult and men can only stand Very short shifts. It is notunusual in an old formation to remove as much as thirty tons of slag andfrom eight to ten hours invariably are required for this phase of theshut down.

When the kiln is returned to the production line, it must pass throughthe fire up period. With comparatively new installations, not many hoursare required before quality of production is resumed. However, in theolder plants several days often are required to regain a state ofbalance. It, of cource, is necessary to reheat the lining after such aslag removal operation. Maintenance costs for the refractory linings canbe rendered extremely high if rapid reheating of the lining is resortedto. This is due to the fact that the lining may have taken on surprisingquantities of moisture as a result of the length of the shut down periodand prevailing atmospheric conditions.

With equipment which is in good condition and with an efficientorganization, it is possible to accomplishthe above referred to cycle ofslag removal in approximately forty-eight to seventytwo hours. As theoperating value of the average rotary kiln is usually calculated to befrom twenty-five dollars to fifty dollars per hour and as slag formationis such a serious factor in some kilns that shut downs every eight tofourteen days are considered necessary, it is not difficult to estimatethe loss in operating value which confronts the management of this typeof equipment.

It is the primary object of this invention to provide a method andapparatus for completely removing fire rings from rotary kilns withouthaving to burn out the charge or shut down for a chilling off period toenable men to enter the kiln, whereby damage to the refractory lining isavoided and a great saving in operating time is effected.

A still further important object of the invention is to provide a methodand apparatus for removing the entire fire ring from a rotary kiln bybreaking the slag into large chunks which can be discharged by rotatingthe cylinder with the result that serious contamination of the productis avoided.

A more specific object of the invention is the provision of apparatus ofthe above mentioned character which is manipulated by workmen operatingat the side of the kiln, in the vicinity of the fire ring, whereby thebreaking up of tho fire ring into large chunks and the completeseverance of the same from the refractory lining may be accomplishedwithin a very few minutes after rotation of the cylinder has beenstopped.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings forming a part of this specification and inwhich like numerals are employed to designate like parts throughout thesame,

Figure l is a fragmentary side elevational view of a rotary kiln at thelocation of a fire ring and with a portion of the apparatus of thisinvention properly applied thereto,

Figure 2 is a vertical sectional View taken on line 2-2 of Fig. l butdiscloses the kiln cylinder as having been rotated approximately 45 sothat the remainder of the apparatus of this invention may be appliedthereto and properly positioned for performing its intended operation.

Figure 3 is a fragmentary, enlarged, vertical sectional View taken onthe plane of the section shown in Fig. 2 and illustrating a completeoperative assembly of the fire ring removing apparatus embodying thisinvention,

Figure l is a detail perspective View of a refractory lining retainingblock,

Figure 5 is a detail perspective view of an anchoring device for theblock of Fig. 4,

Figure 6 is a detail elevational view of a carbon dioxide cartridgeclamping device which forms a part of the apparatus embodying thisinvention, and

Figure 7 is a detail elevational vi w of a detachable handle which isapplied to a carbon dioxide. cartridge to facilitate manipulation of thelatter.

In the drawings, wherein for the purpose of illustration are shown thepreferred embodiments of this invention, and first particularlyreferring to Figs 1 to 3 inclusive, the reference character itdesignates the steel shell of the rotatably supported kiln cylinder. Asthis invention is only concerned with the removal of the fire ring Hwhich has formed in the bore of the cylinder, the portion of the lengthof the cylinder which contains the fire ring is all that has beenillustrated. A refractory lining E2, of suitable thickness, isconventionally applied to the interior of the shell or cylinder Hi. Thisrefractory lining is usually formed of bricks but no attempt has beenmade in the aforementioned figures to specifically illustrate thisparticular type of lining construction. This refractory lining must bereplaced many times during the working life of a kiln and, of course;the kiln must be completely disclosure of the apparatus given in thedrawings is an installation of that character. It is possible, however;to install the permanent portion of the apparatus in a kiln which isprovided with a lining which is in entirely satisfactory condition and,for that reason, is not ready to be replaced. The slight structuralvariations required to install the apparatus on a kiln which is providedwith a lining will be explained as the deextends a few inches into thelining,=it will-serve as a suitable anchor for the latter; With thelining anchored in this way i at the several ports,

formed in this manner, the remainder of the lining can be cut through ateach of these ports by working through the bores of the sleeves orpipesections. By exercising a reasonable amount consideredas involvingapproximatelya ten to 'twenty foot portion of the kiln interior.

While the kiln is shut down for the installatio of a new lining, fourrows of holes l3 are cut in the steel shell or cylinder 10. Theserows ofholes are equally spaced around the periphery of the shell and the holesof each row may be located with from two to threefoot centers. Each holeneed only. be approximatelythree inches in diameter. Fig. 1 disclosesfour such holesin each row. It is to be understood, however, that agreater or lesser number may be provided, if desired. i i i Fig.5discloses an anchor member M. This anchor may either be formed in onepiece, as shown, or three separate pieces may be provided. This anchoris attached, as by welding, to the inner surface ofthe shell or cylinderI0 so as to surround a hole or port l3. One of these anchors is providedfor each one of these ports. The two parallel sides of the anchor areintended to extend longitudinally of the cylinder. The

third side extends circumferentially and is placed on the down-slopeside of its port, as is clearly illustrated in Fig. 1. i

This anchor M is employed for holding in place i the block I5, which isdisclosed in detail inFig. 4.

This block is formed of two ordinary kiln liner bricks Ma and I5!) whichare cored to-provide the opening IS therethrough. This two part blockmay be slipped into the anchor I i through the open, up-slope side ofthe same. After the several anchors l4 and blocks l5 are properlypositioned, the refractory lining 12 may be constructed. The severalblocks l5 perform the very im portant function of holding or retainingthe line ing against circumferential shifting. The core portions it ofthe several blocks [5 areintended to register with the ports or openings83 formed in the shell or cylinder l8. These cores it and the ports l3provide passages from the exterior of the shell or cylinder H] to theinterior of the lining i2. aa 7 a If an installation is to be made in akiln which is already provided with. a refractory lining, the

installation of retaining means for the lining can extending the portsor openings partly through the refractory lining. Ametal sleeveorsection of pipe then may be inserted through each port and thepart'iallyformed hole in the lining and Welded in place. If this sleeveor pipe section of care in extending these holes through the lining, nodamage to the latter will result.

Each port I3 is then provided with an exterior reinforcing plate I!which is provided with a central opening I8 that registers with itsrespective port I3. These plates are rolled to provide a curvature whichcorresponds with that of the periphery of the steel shell or cylinder50. These discs or plates I! are welded to the shell or cylinder i0. Apipe sleeve I9 isthen Welded to each plate l7, This pipe sleeve, ofcourse, is internallyscrew-threaded at 20QA pipe plug 2!, see Figs. 1andZ, is then threaded intofeach one of the pipe sleeves I 9 forclosingthe several ports. The kiln is then ready to be returned to theproductionline. e i

While in operation, the fire ring H will start forming and will continueto build up until loss of draft controllowers the efiiciency of the kilnto a point where removal of the ring becomes necessary. I l

A suitable number of carbon dioxide charged cartridges are employed foractually accomplishing the step of breaking up the slag formation intolarge chunks which can be discharged from the kiln while thelatterisrotating. Onesuch cartridge22 is shown in Figs. 2 and 3. For aclear understanding of the'detail features of construction and mode ofoperation of this cartridge, reference may be made to the patent issuedto Frank H, Armstrong on December 26, '1933, whichbears No. 1,941,196.Briefly described, the cartridge includes a main body which is ofhollowconstruction and which has a discharge cap at one end that isprovided with a plurality of radially directed ports. The other end ofthishollow main body is closed by a charging cap through which theinterior or chamber of the body is charged with liquid carbon dioxide ata pressure of approximately 1000 poundsper square inch. The dischargecap has heater unit is electrically ignited and burning of i the sameeffectsgasification of the liquid charge. When the'desired pressure isreached, thetime required being only a fraction of a second, thegasified carbon dioxide is released by rupturing of the aforesaid walland the charge passes through the discharge cap and isdeliveredradiallytherefrorn through the several ports. This highlycompressed carbon dioxide gas is released at a pressure in theneighborhood of 15,000 pounds per square inch It enters the veins andcrevices or. cracks of the material into which it is discharged. Theexpanding of this gas ex;- erts a slow; heaving fo rce against thematerial which e1fectively breaks upthe latter into large chunks; q,

Referring specifically to Fig,'3, the body of thistype of cartridge isdesignated by the reference character 23.. The charging cap is disclosedat 24 while the discharge cap, with its radial port, is designated bythe reference character 25.

For the purpose of attaching one of these cartridges 22 to the kiln at aport 73, a suitable length of pipe 26 is provided. A sleeve 2'! iswelded exteriorly of the pipe. This sleeve is externally screw-threadedat 28 so that it may be threaded into the sleeve l9 which is permanentlyattached to each port reinforcing plate ll. The outer end portion ofthis pipe section 25 is longitudinally slotted, as at 29, so that thisend of the pipe can be contracted to firmly clamp the cartridge 22within the bore of the pipe. Figs, 3 and 6 disclose the yoke type ofclamping device 30 which is employed for contracting the slot ted end ofthe pipe so as to firmly anchor the cartridge Within the bore of thepipe.

A suitable handle 3! is permanently attached to the pipe section .26 tofacilitate threading its sleeve or bushing 21 into the pipe sleeve I9. Adetachable handle 32 is clamped on the cartridge 22 to facilitateinsertion and withdrawal of the same with respect to the bore of thepipe section 26.

Assuming now that the fire ring if has arrived at a condition where itmust be removed,

the plugs 2| are threaded out of three or four of the pipe couplings l9located in two diametrically arranged lines of ports of the kiln. Theuse of three of these ports in each of the two lines frequently will besufficient but all four ports of each line may be necessary undercertain ring formation conditions. An ordinary jack hammer, using inchsteel and a bit spread of about 2 inches, then is employed for providinga-pocket 33 in the fire ring H in alignment with each port which isopened up by the removal of its plug 2!. This pocket 33 should be formeddeep enough to accommodate the discharge end of the cartridge 22 withthe ports of the discharge cap 25 located from one to two inchesinwardly of the inner face of the refractory lining l2.

The kiln, preferably, is positioned so that one line of opened portswill have their axes arranged at approximately a ninety degree anglewith respect to the floor underlying the kiln. When in this position,the required three or four carbon dioxide cartridges are positioned inthe ports and are fired one or more at a time. These three or four shotswill cause a trench to be cut the full length of the fire ring. Thistrench is produced by the liberated carbon dioxide gas charges which, asa result of their heaving action, dislodge the slag ring in the form oflarge chunks. The trench thus formed extends the full depth of the ring;i e., the slag formation is entirely freed from the refractory lining l2and leaves the inner surface of the latter exposed.

Aiter the formation of one such trench, the kiln is rotated a hundredand eighty degrees to position the second line of prepared ports in theposition occupied by the first used ports. Three or four cartridgecharges are then released on this side of the kiln and a second trenchis formed by the displacement of the slag in the form of large chunks.

With these two trenches formed in the fire ring, rotation of the kilnwill frequently allow each half of the slag formation remaining inposition to break loose and drop free from the face of the kiln lining,however, it is on occasion necessary to assist the drop by one or morecartridges strategically positioned in the ports of the unused rows. Asthe kiln continues to revolve, these chunks of slag are fed or movedtoward the discharge end of the kiln, As these chunks approach thedischarge point of the kiln, some of the larger sized ones may be indanger of damaging the coal feed pipe. These large chunks, however, arenear enough to the discharge end of the kiln to be easily broken up sothat they will pass the coal pipe without danger of damaging the same,

It has been definitely established that an experienced crew of three orfour men, having all of the equipment available and ready for use, canperform the operation of completely removing the fire ring in fromone-half to three-quarters of an hour. After this extremely short shutdown period, the kiln may be put back in operation with the fire ringcompletely removed therefrom.

Figs. 1 and 2 disclose the provision of four rows of ports through thekiln wall. Ordinarily, two diametrically arranged rows are all that needbe provided. However, these two additional rows of ports can be employedto accomplish slight modifications of the previously describedprocedure. For example, a desired number of cartridges may be firedthrough each one of these four rows by starting with any one row andproceeding circumferentially of the kiln cylinder in either direction.By thus utilizing the succeeding rows, the slag formation can be brokenloose in four sections instead of the two previously described halfsections. This procedure may be preferred if it is found that the halfsections are reluctant to break loose and drop after cutting twodiametrically arranged trenches.

It is to be understood that I do not desire to be limited to the exactorder of steps as they have been disclosed, for variations andmodifications of the same, which fall within the scope of theaccompanying claims, are contemplated. It further is to be understoodthat the particular type of apparatus herein shown and described is tobe taken only as a preferred example of the invention, and that variouschanges in the shape, size, and arrangement of parts may be resorted towithout departing from' the spirit of the invention or the scope of thesubjoined claims.

Having thus described the invention, I claim:

1. A method of removing fire rings from rotary kilns, comprisingsuddenly releasing a preconditioned charge of highly compressedcarbondioxide gas simultaneously in a plurality of radial directionsinto each one of a series of relatively shallow, longitudinally andcircumferentially spaced pockets formed in the periphery of the ringformation to cause the expansion of the gas to separate the ring fromthe kiln lining and break up the same into large chunks, and rotatingthe kiln to move the chunks to and spill the same from the discharge endof the kiln.

2. A method of removing fire rings from rotary kilns, comprisingsuddenly releasing a preconditioned charge of highly compressedcarbondioxide gas through each one of a longitudinally aligned series ofspaced openings formed in the wall of a kiln and into the region of theperiphery of the ring formation to cause the expansion of the gas toseparate from and break up 2,301,855 into large "chunks a; sufiicientamount of the formation to produce a trench extending throughout thelength and depth of the ring, repeating the aforesaid trench formingoperation at a location spaced.circumferentially of the ring, rotatingthe kiln to cause the portions of the ring lying between said trenchesto. pull loose from the kiln lining and break up into large chunks as aresult of falling, and continuing rotating the kiln until the saidchunks have been moved to and spilled from end of the kiln.

3. A method of removing fire rings from rotary kilns, comprisingreleasing a number of charges of highly compressed gas through alongitudinally aligned series of spaced openings formed in the fall ofthe kiln and into a corresponding number of shallow pockets formed inthe .periphery of the ring formation to cause the expansion of the gasto dislodge and break up into large;

chunks a suificient amount of the formation to produce a trenchextending throughout the length and depth of the ring, repeating theaforesaid trench forming operation at a location spaced.circumferentially of the ring, rotating the kiln to causethe portions ofthe ring lying between the trenches to pull loose from the kiln liningand be broken up into large chunks as a result of falling, andcontinuing the rotation of the kiln until the said chunks have beenmoved to and spilled from the discharge end of the kiln.

4. A method of removing fire ringsfrorn rtary kilns, comprising cuttinga number of relatively spaced pockets in the periphery of the ringformation, successively releasing into each one of said pockets a chargeof highly compressed gas to cause expansion. of the gas to separate 'thering from the kiln lining and break upthe same into large chunks, androtating the kiln to move the chunks to and spill the same from thedischarge end thereof.

5. A method of removing fire rings from rotary kilns, comprising cuttingtwo circumferentially spaced, longitudinally arranged rows of shallowpockets in the periphery of the ring formation, successively releasinginto the pockets of first one row and then the other a charge of highlycompressed gas to cause expansion of i the gas to separate the ring fromthe kiln lining rotary kiln formed of a shell provided with a hrefractory lining and having an opening extending through said shell andlining where the fire ring of the kiln forms, of a container confining acharge of liquid carbon dioxide which is to be gasified for producing acharge of highly com-. pressed gas, said container having dischargeopenings at one end through which the gas charge is released, and meansfor attaching said container to the kiln shell With the discharge end ofthe container extending into the opening formed in the shell and liningso that the expanding force of the charge of gas, when released, may beapplied to the peripheral portion of the fire ring to break the latterloose from the kiln lining.

'7. Fire ring removing apparatus of the type described, comprising thecombination with a rotary kiln formed of a shell provided with arefractory lining and having an opening extending through said shell andlining where the fire ring the discharge ofthe kiln forms, of acontainer confining a i charge of liquid carbon dioxide which is to begasified for producing a charge of highly compressed gas, saidcontainerhaving discharge, openings at one end through which the gas isreleased, and means for attaching the container to the kiln shell withthe discharge end of the container extending into the opening formed inthe shell and lining so that the expanding force of the charge of gas,whe n released, may be applied-to the peripheral portion of the firering to break the latter loose from the kiln lining, said containerattaching means comprising .a sleeve permanently attached to the shellin alignment with its opening, and securing means detachably connectedto the container and the sleeve for holding the container in placeduring the release of the charge. i

8- Fire ring removing apparatus of the type described, comprising thecombination with a rotary kiln formed of a'shellprovided with a'refractory lining and having an opening ,extendmg through said shell andlining where the fire ring of the kiln forms, of a container confining acharge of highly compressed gas, said container having dischargeopeningsat one end through which the gas charge is released, andmeansfor attaching the container to the kiln shell with the discharge end. ofthe container extending into the opening formed in the; shell and liningso that the expanding force of the charge of gas, when released, may beapplied to the peripheral portion of the fire ring to break the latterloose from the kiln lining, said container attaching means comprising asleeve permanently attached to the shell in alignment with said opening,a second sleeve detachably connected to thefirst sleeve, and means fordetachably connectingthe container to the second sleeve for holding thecontainer charge.

9. liire ring removing apparatus of the type described, comprising thecombination with a rotary kiln formed of a shell provided with arefractory lining and having an opening extending through said shell andlining where the fire ring of the kiln forms, of a container confining acharge of highly compressed gas, said container having dischargeopenings at one end through which the gas charge is released, and meansfor attaching said container to the kiln shell with the discharge end ofthe container extending into.

the opening formed in the shell and lining so that the expanding forceof the charge of gas, when released, may be applied to the peripheralportion of the fire ring to break the latter loose from the kiln lining,said container attaching means comprising a sleeve permanently attachedto the shell in alignment with said opening, a second sleeve detachablyconnected to the first sleeve, a, tubular mounting member permanentlyfastened to the second sleeve and having. the container positioned inits bore, and means for detachably securing the container in the mount:ing means.

10. Fire ring removing apparatus of the type described, comprising thecombination with a rotary kiln formed of a shell provided with arefractory lining and having an opening extending through said shell andlining where the fire ring of the kiln forms, of a container confining acharge of highly compressed gas, said container having dischargeopenings at one end through which the gas charge is released, and meansfor attaching the container to the kiln shell with in place during therelease of the,

the discharge end of the container extending into the opening formed inthe shell and lining so that the expanding force of the charge of gas,when released, may be applied to the peripheral portion of the fire ringto break the latter loose from the kiln lining, said container attachingmeans comprising a sleeve permanently attached to the shell in alignmentwith said opening, a second sleeve threadedly connected to the firstsleeve, a tubular mounting member permanently fastened to the secondsleeve and having the container positioned in its bore, handle meansattached to the mounting member to facilitate connecting the twosleeves, and means including a clamp for detachably securing thecontainer in the mounting member.

11. Fire ring removing apparatus of the type described, comprising thecombination with a rotary kiln formed of a shell provided with arefractory lining and having an opening extending through said shell andlining Where the fire ring of the kiln forms, of a container confining acharge of highly compressed gas, said container having dischargeopenings at one end through Which the gas charge is released, and meansfor attaching said container to the kiln shell with the discharge end ofthe container extending into the opening formed in the shell and liningso that the expanding force of the charge of gas, when released, may beapplied to the peripheral portion of the fire ring to break the latterloose from the kiln lining, said container attaching means comprising asleeve permanently attached to the shell in alignment with said opening,a tubular mounting member for the container, means for detachablyconnecting the container to the mounting member, and means fordetachably connecting the mounting member to the sleeve.

12. Fire ring removing apparatus of the type described, comprising thecombination with a rotary kiln formed of a shell provided with arefractory lining and having an opening extending through said shell andlining Where the fire ring of the kiln forms, of a cartridge confining acharge of highly compressed gas, said cartridge having a dischargeopening at one end through Which the gas charge is released, a mountingmember, means for attaching the mounting member to the cartridge at theproper location relative' to the length of the cartridge so that Whenthe cartridge is attached to the kiln shell the discharge end of thecartridge will be positioned to apply the released gas charge to theperipheral portion of the fire ring to break the latter loose from thekiln lining, and means for detachably securing the said mounting memberto the kiln shell to properly position the cartridge.

WALTER R. CLIFFE.

